Chapter 12-Ceiling Collapse Flashcards
Ceiling are NON LOAD BEARING structural elements that support ONLY their weight
Their collapse DOES NOT cause collapse of other structural parts
*ceilings can drop over FF’s and TRAP them inside burning buildings
2 Types of Ceilings :
- DIRECTLY AFFIXED to the floor or roof joist above
2. SUSPENDED several inches or feet below the joists by vertical strips of wood, steel hangers, or thin wires
Older buildings–LATH/PLASTER ceilings :
- strips of wood or wire lath nailed to the underside of the lath
- several coats of wet gypsum plaster, applied to the underside of the lath
New buildings use DRY GYPSUM BOARD:
-4’x8’ area, 1/4” to 3/8” thick, nailed directly to the underside of the joists
Less common: ornamental tin/wood paneling
At fires – DIRECTLY AFFIXED CEILINGS, usually collapses in SMALL PIECES, rather than in one large section…
USUALLY does NOT cause serious injury
Collapse of Ceilings is often cause by ?
WATER ABSORPTION from hose stream
When plaster is only _____thick and the FF is equipped with a properly fitted helmet…there is usually no serious injury?
1-2 inches thick
IN OLDER structures, where plaster ceilings are ______thick and _____height , the collapse of a large area of thick heavy plaster can knock a FF unconscious or cause serious head/neck injury?
3-4 inches
15-20 feet
Degree of injury caused by collapsed plaster is based on:
- thickness of the falling plaster
- height of the ceiling from which it falls
- condition of the cushioning system inside the members helmet
Most dangerous ceiling is ?
SUSPENDED CEILING
aka drop/hanging ceilings
Suspended ceilings most often found in 3 types of occupancies?
- STORES
- RENOVATED BUILDINGS
- TOP FLOOR OF MD’S
Constructed several inches or feet below the supporting roof or floor joists above
ceiling hangs below the joists-connected by vertical hangers that may be STRIPS OF WOOD, OR THIN WIRE
STORES-covers old fashion ceilings
MD’s(top floor)-creates space to insulate a top floor from SUN RAYS
Renovated-every floor of every apartment and is used to reduce the floor height to conserve energy for HEATING/Cooling
Suspended ceiling presents a serious hazard to FF’s ..
when if fails, at fires, the ENTIRE GRID FRAMEWORK , in addition to ceiling sheathing , collapses
The ceiling grid system can weigh ______?
SEVERAL THOUSAND POUNDS
FF caught below could :
- become trapped in a void and crawl out
- trapped inside small sealed void space at rear or pinned beneath the heavy ceiling grid
also rapid fire increase after suspended ceiling collapse
3 common Suspended ceilings ?
- Wood grid system with permanently affixed ceiling
- metal grid system with a permanently affixed ceiling
- Lightweight metal grid system with removable panel ceiling
Part of suspended ceiling which traps or pins FF is ?
GRID SYSTEM/FRAMEWORK behing ceilings sheathing
What is the heaviest part of suspended ceiling ?
GRID SYSTEM
Which suspended ceiling does NOT pin FF’s?
lightweight grid system with removable ceiling panels
What determines seriousness of Entrapment hazard?
WEIGHT of suspended ceiling
Average weight of lightweight metal ceiling is ?
1 pound per square foot
with permanently fixed wire lath -10 pounds per square foot
Fire can enter suspended ceiling through:
- fire burns through ceiling directly above
- louvered openings used to transfer air to and from the plenum
- holes for recessed lighting fixtures that are NOT FIRE STOPPED
- fire burns through POKE THROUGH HOLE created by a light fixture or pipe recess
- removable panels that are removed and not in place or improperly replaced
FF’s should open these ceilings with a ?
PIKE POLE
- may discover several layers of concealed space
- FF’s must check every layer
Some old Commercial occupancies have 2 ceilings and 2 concealed spaces:
- there is a concealed space behind the original ceiling of tin or lath/plaster
- and a concealed space above an added suspended ceiling of a lightweight metal grid system with removable panels
When a 2nd suspended ceiling is constructed, NUMEROUS HOLSE are punched through the first –these create avenues for fire travel in all 3 ceilings
When MULTIPLE suspended ceilings are discovered , Notify ?
INCIDENT COMMANDER
Current NYC building code requires?
-BLACK IRON rod AND FRAME CEILING SUPPORT–redistributes loads during partial failure during fire
The CEILING collapse killing FF’s is ?
WOOD GRID SUSPENDED CEILING
Immediately after a wood grip suspended ceiling collapses, there is sometimes a RAPID increase in fire in the space directly over fallen ceiling
When a fire is SMOLDERING in a space above a suspended ceiling , and the ceiling collapses, a large inrush of fresh air enters the space above the fallen ceiling, fill the vacuum and is mixed with SUPERHEATED GASES AND HEAT….an EXPLOSIVE FIRE MAY OCCUR
- wood grid will FUEL the fire
- very LITTLE TIME to rescue FF;s below
FIRST STEP to rescue members under collapsed ceiling DURING A STORE FIRE is to?
SWEEP the collapse area ABOVE THE CEILING with a hose line and knock down the flames
a LADDER should be ready at every fire to rescue trapped victims or firefighters suddenly trapped by ceiling and fire
BEFORE committing members to a serious fire in a large area occupancy, an OFFICER should know ?
TYPE OF CEILING in structure
- if suspended , NOTIFY IC
- officers can order the ceiling opened up and examined asap
When examining multiple ceilings?
FF should open up and SEE ROOF OR FLOOR JOISTS
more than one ceiling–EACH CEILING MUST BE EXAMINED
-spreading fire–consider defensive strategy
Proper method of OPENING ceiling with a PIKE pole?
PULL DOWN SHEATHING , NOT GRID SYSTEM
PULL DOWN WOOD LATH, NOT FURRING STRIPS
AT SERIOUS fires where suspended ceiling collapse is POSSIBLE:
members should stay near large pieces of furniture or stock for SHELTER
OPEN FLOOR AREA is dangerous
Shoring:
PORTABLE LADDER CAN BE used TO SHORE UP CEILING
Ceiling dismantling and rescue:
GRID SYSTEM must be cut apart with POWER SAW
- then ceiling sheathing must be cut or pulled apart
- FF’s can then crawl beneath into shelters searching for victims
Portable Ladder can be used for ?
TUNNELING-raising lever
-this may allow FF’s to crawl beneath a fallen ceiling or break up a ceiling if the grid system is lightweight
TOP FLOOR FIRES in MD’S and Renovated Dwellings:
A fF should remain at the TURNTABLE of a ladder to be ready to rescue FF trapped by a ceiling collapse who comes to a window to escape the ensuing Fire
Rescue attempts from adjoining stores:
- a partition wall, separating stores in a large one story building , can be penetrated FASTER, then rear masonry wall
- windows and stores at rear are usually bricked up or locked
- hose lines should be positioned into adjoining stores to prevent fire spread
Entry into store beneath a ceiling collapse can sometimes be achieved from below:
going down an outside cellar entrance may allow access to the store via an interior cellar entrance
IC should:
- limit the number of members participating in the rescue attempt
- WEIGHT of rescuers can be greater than weight of fallen ceiling and can crush members trapped below
Stability of suspended ceiling in question:
- make an INSPECTION opening in the ceiling with a pike pole near the entrance
- check for fire in the space above the suspended ceiling before you enter the room
- if the ceiling suddenly collapses you have a better chance to escape
